science happens within a culture
TRANSCRIPT
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1/10/14 Warm Up Turn in your Toothpick Fish Lab’s to the basket when your warm-up is complete.
1. Which fish colors were advantageous (survived) during the first 4 generations? Why was this?
2. Why did the green alleles disappear from the gene pool after the natural disaster?
The Theory of Evolution
Science happens within a culture
TINTORETTO The Creation of the Animals 1550
Then along comes Darwin…
1831-1836 22 years old!
Warbler finch
Woodpecker finch
Small insectivorous
tree finch
Large
insectivorous
tree finch
Vegetarian
tree finch
Cactus finch
Sharp-beaked finch
Small ground
finch
Medium
ground finch
Large
ground finch
Insect eaters
Bud eater
Seed eaters
Cactus
eater
Then along comes Darwin…
Ancestral species
Descendant species
& those dang finches!
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What Darwin Saw Observations Questions
Many beetle species Why so many?
Plants/animals well suited to environment. Why? How?
Many ways to survive and reproduce. Was there a process that led to this variety?
Grasslands on different continents had different animals. Why?
No rabbits in Australia Why?
No kangaroos in England? Why?
Fossils resembled organisms still alive. How are they related?
Some fossils looked different than living organisms Why did they disappear?
Tortoises in Galapagos varied depending on island they were from.
Why/How were they so well suited?
Finches in Galapagos varied depending on island they were from.
Why/How were they so well suited?
Different climates on different islands. How did this affect life there?
Different beaks on birds depending on their food. How did this happen?
Plants and animals varied noticeably on different Galapagos islands.
Were they once members of the same species?
Video Clip #2
Glyptodont fossils
Modern armadillos Modern sloth
Sloth fossils
Why should extinct species & living species
be found on the same continent?
Darwin’s Work Darwin collected many insects, plants,
and small animals
He would make detailed notes about their behavior, then preserve them and observe their physical features
He sent all his specimens and notes back to England
Darwin’s Influences 1. Thomas Malthus – wrote about population growth
in London
Darwin noticed more animals were born than could survive
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2. Charles Lyell – said Earth was very old due to rate of geological processes
To Darwin, this meant there was enough time for organisms to change and branch out.
3. Farmers and Breeders
Ex. Dog varieties
Artificial Selection – humans breeding plants and animals with the characteristics they want.
Darwin’s reasoning He thought…
The struggle to survive causes only the most “fit” genes to be passed on to the next generation (struggle for existence). Only the best-fit individuals survive and get to pass on their traits to offspring.
Darwin’s Reasoning He thought….
Evolution occurs as advantageous traits accumulate in a population. The frequency of an allele within a population changes.
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Publishing His Research Alfred Russel Wallace – developed his own ideas
on species formation
“On the Origin of Species” – 1859, Charles Darwin
2 Ideas:
1. Descent with Modification
Plants/animals change
LOTS of time
Extinction
Environments change
2. Natural Selection
Variation
Time
Advantage/Selection